Washington (CNN) - The war of commercials from the presidential campaigns and various super PACs supporting candidates is expected to intensify in the coming days and to greatly expand in its scope.

Mitt Romney's campaign has now bought almost $1.2 million in ad time in Michigan, a source who tracks media buys told CNN. So far the campaign has up a positive spot in the state where the candidate talks about his Michigan roots. His campaign did not respond to a request for comment regarding its ad strategy.FULL POST